Around 3:50 yesterday afternoon, I looked at my Facebook page and was puzzled to read a post by someone of my acquaintance saying simply that she was “safe.” I was tempted to ask her what she had been up to that might have put her in danger, but as I looked further down the page, it became apparent that something terrible had happened that affected quite a few people. I went to a news site and was horrified to learn of the deadly violence that had struck in Copley Square an hour previously, about three miles away from where I sat.

I am glad to be able to say that, so far as I have learned, no one of my acquaintance was among those killed or injured by the blasts. But I think all of us who live in the area feel in some obscure way wounded by it.

And then there are those who have quite different reactions. My previous entry on the Westboro Baptist Church has been made somewhat more timely by the group’s announcement on its Twitter feed that it proposes to show up at the funerals of victims of yesterday’s incident. The Phelpses close their message with the assertion that “GOD SENT THE BOMBS IN FURY OVER F*G MARRIAGE!” I once remarked in this blog that natural disasters have a tendency to bring forth self-nominated prophets, ready to invoke divine causes for natural events. But those who consider themselves privy to divine intentions are also ready to render the same public service when sorrow is brought about by human hands, as shown by Pat Robertson and Jerry Falwell in their remarks shortly after the attacks of September 11, 2001 (observed in the third indented paragraph in this blog entry).

But you don’t have to believe in supernatural causes to reject the most obvious natural causes of events: you may simply believe in vast hidden conspiracies, in the manner of apopheniac extraordinaire Alex Jones, who needed little evidence before declaring that the bombings were yet another false-flag operation by the United States government. (Added after posting: Elisabeth Parker at Addicting Info shows how Alex Jones rearranges the dots so that he can connect them.)

The Phelpses and Alex Jones are clearly extreme examples of systematic cognitive (and, at least in the case of the Phelpses, not just cognitive) distortion. But even those of us who do not go to such extremes as a rule may be blown a bit off course by the force of an extraordinary event like this. One looks about with apprehension and suspicion, on guard for signs of the “next” attack, though in fact, the time and place of one such extraordinary event are among the least likely for the occurrence of another. Terrorist acts do occur, but in these parts it stands to reason that one is in less danger of one happening now than one was before yesterday’s incident. Bruce Schneier puts the point well in a piece published on the day of the event in The Atlantic on line:

. . . Terrorism is designed precisely to scare people—far out of proportion to its actual danger. A huge amount of research on fear and the brain teaches us that we exaggerate threats that are rare, spectacular, immediate, random—in this case involving an innocent child—senseless, horrific and graphic. Terrorism pushes all of our fear buttons, really hard, and we overreact.

But our brains are fooling us. Even though this will be in the news for weeks, we should recognize this for what it is: a rare event. That’s the very definition of news: something that is unusual—in this case, something that almost never happens.

When we learn of a terrorist attack, we naturally follow what in cognitive psychology is called the availability heuristic, which is the natural human tendency to estimate the probability of an event of a certain class according to the “availability,” in our minds, of instances. The stronger the emotional charge on an instance, the more readily it comes to mind, and the more we tend to overestimate the probability of an event of that kind occurring. We do not necessarily fall into the craziness of religious maniacs and conspiracy fantasists, but our cognitive game is certainly below its best. Terrorism works by playing on this cognitive weakness, and making us feel that we are in much more danger than we actually are.

Schneier follows his observation with an instructive historical reminder:

Remember after 9/11 when people predicted we’d see these sorts of attacks every few months? That never happened, and it wasn’t because the TSA confiscated knives and snow globes at airports. Give the FBI credit for rolling up terrorist networks and interdicting terrorist funding, but we also exaggerated the threat. We get our ideas about how easy it is to blow things up from television and the movies. It turns out that terrorism is much harder than most people think. It’s hard to find willing terrorists, it’s hard to put a plot together, it’s hard to get materials, and it’s hard to execute a workable plan. As a collective group, terrorists are dumb, and they make dumb mistakes; criminal masterminds are another myth from movies and comic books.

I’m taking a plane trip soon, and I am not eager to learn what additional inconveniences I shall have to endure. That is a much more realistic worry, I think, than any suspicion of another attack.